Sealed telescopic connection



June 7, 1960 H. ALLEN 2,939,534

SEALED TELESCOPIC CONNECTION Filed April 10, 1956 f IN VENTOR.

United States Patent SEALED TELESCOPIC CONNECTION Herbert Allen,Houston, Tex., assignor to Cameron Iron Works, Inc., Houston, Tex., acorporation of Texas Filed Apr. 10, 1956, Ser. No. 577,325

2 Claimsv (Cl. 166-86) This invention relates to a novel sealedconnection between a pair of telescopically arranged members; and, moreparticularly to such a connection in which the seal is formed as themembers are threadedly made up with one another. 1

In the completion and reworking of oil and gas wells, it is frequentlynecessary to pass a variety of tools into the well tubing throughpassages in the wellhead equipment from which the tubing is suspended.Obviously, it is desired to keep the tubing and Wellhead size to aminimum by having the minimum inside diameter of the tubing and thepassages approximate the maximum outside diameter of such tools asclosely as possible.

One of the more commonoperations in well completion and reworking is thelocation of a valve fixedly within a passage in the wellhead above thetubing to prevent the flow of production upwardly therethrough. Aconnection of the general type contemplated by this invention isespecially useful in this connection for it permits the valve to besealed and fixedly located within the passage as it is extended axiallytherethrough. Thus, it has been proposed to form this sealed joint bymeans of complementary shoulders on the valve and wellhead passage whichare adapted to be brought into abutment to form a metal-to-metal seal asthe valve is threadedly made up within the wellhead. In such a case, theouter diameter of the valve at the shoulder necessitates that theminimum inside diameter through the upper portion of the wellheadpassage be correspondingly larger than the minimum inside diameter ofthe well tubing, and thus the maximum out-side diameter of the tool.

An object of this invention is to provide an improved telescopic sealedconnection of this general type in which the maximum outside diameter ofthe male member need only exceed the minimum inside diameter of thefemale member by approximately the depth of the threads by which theyare made up with one another.

Another object is to provide a sealed telescopic connection of thecharacter described in the foregoing object in which a desired degree ofpressure may be applied to the sealing part between the male and femalemembers.

A further object which is pertinent particularly to the environmentabove-mentioned is to provide an improved connection between aback-pressure valve and a wellhead member in which the valve is to betelescopically received, which connection is so constructed that thepassage in the wellhead member through which the valve is extended neednot be appreciably greater than that of the well tubing below thewellhead.

Other objects, advantages and features of this invention will beapparent to one skilled in the art upon a consideration of the writtenspecification, the attached claims and the annexed drawings.

In the drawings, wherein like reference characters are used throughoutto designate like parts:

Fig. 1 is a view, partly in section, of a dual string of well tubingsuspended by hangers within the wellhead, and with a back-pressure valveshown fixedly and seal- 2,939,534 1C6 Patented June 7, 196,

ably located within one hanger by means of the connection of the presentinvention;

Fig. 2 is an enlarged sectional view of a part of the connection as thevalve is being made up Within the hanger, but prior to formation of theseal therebetween; and

Fig. 3 is a view similar to Fig. 2, but upon an additional making up ofthe valve within the hanger to form the seal therebetween.

Referring now particularly to the drawings, there is shown in Fig. 1 awellhead which includes a tubing head and another wellhead member 11,which, as shown in Fig. 1, is a valve, as will be described hereinafter.The member 11 is connected above the tubing head by means ofcircumferentially spaced apart bolts 12 and sealed with respect theretoby an annular ring 13 compressed tightly between oppositely disposedgrooves 14 and 14a in the member 11 and tubing head 10, respectively.Suspended by hangers 15 Within the tubing head are a pair of parallelwell tubings 16 which are adapted to extend to production zones withinthe well and are of a minimum, inside diameter to accommodate thepassage of tools therethrough. As fully described in my copendingapplication, Serial No. 545,079, filed November 4, 1955, and entitledPipe Hanging Apparatus, and now issued as Patent No. 2,794,505, each ofthe tubing hangers 15 is supported from and sealed with respect to thetubing head 10. In the particular embodiment shown in the drawings, thewellhead member 11 is, as previously noted, a valve. However, in anearlier stage of the completion process, a blowout preventer isconnected above the head and the hangers are run through the preventerand into supported position by means of handling joints of tubing. Thehandling joints are then removed and the preventer is replaced by themaster valve 11 which has passages 17 formed therein above each of thehangers. When the -hangers have been landed, the strings are removedthrough the preventer, and the preventer is removed from the head andreplaced by a completion valve. Inasmuch as the other details of thisWellhead installation are not pertinent to the present invention, andare fully disclosed in the above-mentioned copending application,further reference thereto will not be made.

The opening through each of the hangers 15 is provided with a threadedportion 18 for connection with a back pressure valve or similar member19. During the completion process the back pressure valve is loweredwith the hanger through the preventer and then removed therefrom throughthe passage 17 in the completion valve 11 when the well is to be broughtin. Preferably, the minimum inside diameter of the passage through thevalve 11 is larger than the minimum inside diameter of the openingthrough the hanger, which is defined by the inside or extremities of thethreads 18, by only an amount approximating the depth of such threads soas to accommodate passage of the maximum outside diameter of the body ofthe valve 19. The maximum diameter is defined by the outermost portionor extremities of threads 20 on the valve body for mating with threadedportion 18 of the opening through the hanger 15 to telescopicallyconnect the valve within the opening through the hanger. It will beappreciated that the maximum size of tool which may be passed throughthe hanger and into the well tubing 16 is limited by the minimum insidediameter of the hanger defined by threaded portion 18, such that theminimum inside diameter of the passage through the completion valve willbe somewhat larger than that of the well tubing=16. However, inaccordance with the present invention, and as will be appreciated fromthe description to follow, this excess need only be approximately thedepth of the threads by which the valve and hanger are connectedtogether.

The back-pressure valve 19 is made up of a valve body 20a upon the outerdiameter of which are disposed the threads 20, and a passageway 21through the body having an annular seat 22 formed upon an intermediateportion thereof. A valve member 23 is movable within the passage betweenseated and unseated positions with respect to the valve seat 22 forclosing and opening the flow passage 21, respectively. Moreparticularly, the valve member 23 is provided with a stem 24 guidedWithin an opening 25 on the lower end of the valve body, and is urged toa normally closed position by means of a coil spring 26 disposed betweenthe body and the head of the valve member. Thus, when disposed as shownwithin the hanger 15, the valve 19 serves to shut off production flowupwardly through tubing 16.

As is common in the art, the valve is moved into and out of its fixedposition within hanger by means of a stinger or similar tool whichdepresses the valve memher to hold it in an open position. For thispurpose, the upper end of the valve body may be provided with slots 27to accommodate parts of the stinger by means of which a rotary movementmay be imparted to the valve body for making up the threads with thethreaded portion 18 on the passage through the hanger. Also, as can beseen from Fig. 1, the lower end of the valve body is of a spiderconstruction to define the opening while at the same time permitting thefreedom of flow therepast.

Although the connection of the present invention will be described indetail below in connection with the aforesaid valve and wellhead, andeven though it, in fact, has particular utility in such an environment,it should be understood that it is contemplated that the connection mayhave other applications, and the terms of the claims should not belimited to the illustrated environment.

With reference now particularly to Figs. 2 and 3, the connection of thepresent invention includes a seal ring 27 of flowable material, such asrubber or a suitable plastic, disposed annularly of one of the valvebody 20a and hanger 15 for confinement therebetween and deformation bythe threads of the other of the valve body and hanger into sealingengagement therebetween as such members are made up with one another.Thus, the seal ring 27 is disposed in the path of the leading threads ofsaid other member as the two members are made up with one another, sothat the flowable material of the ring will be displaced and thusdistorted in the manner described. In accordance with the presentinvention, these threads bear such a relation to the ring that thelatter is first deformed as the members reach one stage of being made upand then the internal pressure of the confined seal ring is increased toa desired extent as the members are further made up with one another.

More particularly, the seal ring 27 is disposed annularly between thetwo telescoping members for confinement between a shoulder 28a on onemember and the aforementioned threads on the other member. As shown inthe drawings, the ring 27 substantially fills a groove 27a about thevalve body between the threads 20 and one end of a cylindrical surfaceon the valve body at the other side of the ring, said cylindricalsurface and seal ring being of an outer diameter substantially nogreater than the outer portions of the threads 20, but at the same timedisposable closely adjacent inner diameter of a cylindrical surface 18aof the opening through the hanger 15, which inner diameter substantiallyequals that of the root of threads 18 so as to prevent the flow of thering therepast.

As shown, the threads are preferably of a relatively shallowflat-crested type so as to maintain the inside diameter of the wellheadpassage at a minimum while at the same time providing a maximum ofdisplacement of the flowable material of the ring per unit of axialmovement of the threads on the hanger relative to the ring. In thismanner, the threads may easily bear such a cross-sectional area relativeto that of the seal ring 4 so that the ring, as previously mentioned, isfirst distorted into sealing engagement with the cylindrical surface 18aof the hanger opening between the shoulder 28a forming part of thegroove 27a on 'the end of the cylindrical surface 28 and the uppermostthread of the threads 18, such that its internal pressure may then beincreased to a desired degree upon further making up of the valve withinthe hanger. Although the seal ring is shown to be of a substantiallyrectangular cross-section, it may be of an O-ring shape or any otherdesired cross-sectional shape having the desired relationship to thethreads. Furthermore, of course, it is desired that the seal ring notproject too far beyond the outer diameter of the valve body so that itwill not be damaged in any way in passing through the passage 17 andhanger 15.

It will be appreciated that the straight-type threads illustrated arepreferred inasmuch as they permit a great flexibility in theaccomplishment of desired pressure upon the seal ring as there is nolimit to axial movement between the threads. Also, it is preferred thatthe seal ring 27 be carried by the valve as this facilitates removal andreplacement thereof, when desired.

From the foregoing it will be seen that this invention is one welladapted to attain all of the ends and objects hereinabove set forth,together with other advantages which are obvious and which are inherentto the apparatus.

It will be understood that certain features and subcombinations are ofutility and may be employed without reference to other features andsubcombinations. This is contemplated by and is within the scope of theclaims.

As many possible embodiments may be made of the invention withoutdeparting from the scope thereof, it is to be understood that all matterherein set forth or shown in the accompanying drawings is to beinterpreted as illustrative and not in a limiting sense.

The invention having been described, what is claimed is:

1. A sealed telescopic connection, comprising a first member havingthreads and a substantially cylindrical surface whose diametersubstantially equals that of the thread roots, a second member havingthreads for mating with the threads of the first member and asubstantially cylindrical surface of very nearly the same diameter asthe cylindrical surface of the first member for disposal closelyadjacent the cylindrical surface of the first member, an annular groovein the second member intermediate the threads and an end of thecylindrical surface thereof, and an annular deformable sealing ringsubstantially filling the groove and having a diameter substantially thesame as that of the cylindrical surface of said second member, thecylindrical surface of the first member being opposite the sealing ringand cylindrical surface of the second member, as the leading threads ofthe first member engage with the scaling ring during making up of themembers with one another, confining the sealing ring for deformationinto sealing engagement between the first and second members andpermitting the internal pressure of the confined sealing ring to beincreased to a desired degree upon continued making up of said members.

2. A wellhead assembly, comprising a tubing head, a wellhead memberconnected to the upper end of the tubing head, a tubing hanger supportedwithin the tubing head for suspending tubing therefrom and having anopening therethrough which includes a threaded portion and asubstantially cylindrical surface whose diameter substantially equalsthat of the thread roots, means defining a flow passage through thewellhead member in alignment with the opening through the tubing hanger,a back pressure valve comprising a body having threads thereon forconnection with the threaded portion of the opening through the hangerand a substantially cylindrical surface of very nearly the same diameteras the cylindrical surface of the hanger opening for disposal closelyadjacent the cylindrical surface of the hanger opening, an annulargroove in the valve body intermediate the threaded portion and an end ofthe cylindrical surface thereof, and an annular deformable sealing ringsubstantially filling the groove and having a diameter substantially thesame as the cylindrical surface of the valve body, the cylindricalsurface of the hanger opening being opposite the sealing ring andcylindrical surface of the valve body as the leading threads on thehanger opening engage with the sealing ring during connection of thevalve with the hanger, confining the sealing ring for deformation into10 sealing engagement between the hanger opening and valve body andpermitting the internal pressure of the confined sealing ring to beincreased to a desired degree upon continued making up of the valvewithin the hanger, and

5 passage of the valve therethrough.

References Cited in the file of'this patent UNITED STATES PATENTS2,148,327 Smith et al Feb. 21, 1939 2,246,436 Downey June 17, 19412,413,878 Maky Jan. 7, 1947 2,469,074 Mueller May 3, 1949 2,794,505Allen June 4, 1957

